'use strict';

function double_to_one(collection) {
  let arr=(collection+'').split(',');
  console.log( arr);
  let s1=arr.map(function(x){
           return Number(x);
  });
  let result=[];
  for(let item of s1){
      if(result.includes(item)){

      }else{
        result.push(item);
      }
  }
  console.log(result);
 return result; //在这里写入代码
}

module.exports = double_to_one;
